/*
 * JStock - Free Stock Market Software
 * Copyright (C) 2010 Yan Cheng CHEOK <yccheok@yahoo.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

package org.yccheok.jstock.engine;

import java.util.*;
import java.util.concurrent.*;

/**
 *
 * @author yccheok
 */
public class Subject<S, A> {
    
    public void attach(Observer<S, A> observer) {
        if (observers.contains(observer) == false)
            observers.add(observer);
    }

    public void dettach(Observer<S, A> observer) {
        observers.remove(observer);
    }
    
    public void dettachAll() {
        observers.clear();
    }
    
    protected void notify(S subject, A arg) {
        for (Observer<S, A> obs : observers) {
            obs.update(subject, arg);
        }
    }

    private List<Observer<S, A>> observers = new CopyOnWriteArrayList<Observer<S, A>>();    
}
